The Biggest Dam You May Not Have Heard Of

“I’ve actually had people drive right past the dam – and it’s a mile long – then turn around and ask me, ‘Where’s the dam?” says the U.S. Army Corps of Engineers’ Scott Bennett.

That dam is the Chief Joseph, spanning the Columbia River just outside of Bridgeport, Washington near Wenatchee, not far from the U.S.-Canadian border. The Chief Joseph is the second-largest hydropower dam in the United States, after the Grand Coulee, also located in Washington. Chief Joseph produces 2,458 megawatts of carbon-free renewable electricity – enough to power the entire Seattle metropolitan area.

Most people have heard of the Grand Coulee Dam – it’s the most productive dam in the United States, it was immortalized in a Woody Guthrie song, and NASA shows it as a major landmark in photos taken from space. Every summer, the Grand Coulee Dam serves as a projection screen for nightly laser light shows, attracting even international tourists.

But the Chief Joseph Dam is the one that’s getting $168 million worth of new turbine runners – 16 of them – which will increase the Chief Joseph’s output by 6.5 percent. That may not sound like much, but it will mean an additional 53 average megawatts in generation to power homes, businesses, manufacturing facilities and more in the region – enough electricity to power 39,000 homes. The Chief Joseph turbine replacement project will be completed next year.

Where is the 168-million dollars for the upgrade coming from? From power customers throughout the Pacific Northwest, including Central Lincoln’s, through the rates the Bonneville Power Administration charges its utility customers. (In terms of the amount of kilowatts purchased each month, Central Lincoln is BPA’s tenth-largest customer.)

“We’re making a wise investment in efficiency improvements,” says Joseph Summers, the Chief Joseph’s operations power manager. With the new turbine runners, “For the same amount of water, we’re getting more power,” which is crucial in a region where electricity needs continue to grow, as does the need to balance power fluctuations created primarily by intermittent renewable sources of power, which depend on Mother Nature for sun and wind.

There are 31 federally-owned dams in the federal Columbia River Power System, all producing clean, renewable electricity. Those dams are the primary reason electricity rates in the Pacific Northwest remain among the lowest in the country. The result is cleaner air, and lower power bills for the people and businesses of the Pacific Northwest.